I have a PMA Concord 27 amp hr, 24 volt RG battery which was purchased
over two years ago.  I wanted power for the landing gear installation in 90Y
while I was in the construction phase.  Gear swings by the dozens are really
needed to get a good build.  I have a nice, if inexpensive, 6-12-24 volt
battery charger made by Schuer(?) from U.S. Tools and it has worked
perfectly for the last ten plus years.
  I always try to keep the battery charged.  I don't use a trickle charger.
90Y is coming out of upholstery in just over two weeks and I'll be waiting
to see if there is capability left; ie. will Al Campbell have a start.  I
think he will.  After paint I took my charger up to Bend for the reassembly
and test flight but I'm flying commercial this time.
  I found out about the Concord RG batteries at an IA seminar three years
ago.  The Concord rep had an hour to make all of us IA's go to sleep but
that didn't happen.  There was a spirited discussion about the plusses of
the RG type battery.
  It has the internal resistance of a NiCad without any of the problems.
The additional small increment of internal pressure combined with a catylist
helps the gasses of charge and discharge (hydrogen) recombine with the
electrolyte. The cost is about 1/10th of the (in)famous NiCad with its AD's.
The very low internal resistance means the current available on cranking is
substantially higher than a common lead acid battery can provide.  There
seems to be no risk of heat build up which NiCads are known for.
  I have been impressed with the Concord RG battery in 90Y so far.  My
impressions are due to lack of problems to date and good performance.  I
will keep the LML informed, especially should there be a discrepancy.
  I have no interest in Concord Batteries other than personal usage.
Thanks,
Walter Dodson;  N990Y is to be delivered to Albert Goodman on September
21st, 2003.  I can't wait...